Iodine dispenser



.im 27, 1967 J, KEENAN ET AL 3,328,108

IODINE DISPENSER Filed NOV. 22, 1965 74 24 ROB ERT P BONAZOLI JAMES KEENAN INVENTORS ATTORNEY United States Patent O 3,328,108 IGDINE DISPENSER James Keenan, Reading, and Robert P. Bonazoli, South Hamilton, Mass., assignors to Sylvania Electric Products Inc., a corporation of Delaware Filed Nov. 22, 1965, Ser. No. 508,909 7 Claims. (Cl. S16-30) ABSTRACT F THE DISCLOSURE An automatic dispensing head for introducing measured quantities of iodine to a lamp envelope, and through which the lamp can be exhausted and gas-filled. The dispensing head has ya preheated orifice thereby maintaining proper operational environment during the dispensing operation.

This invention relates to dispensers and more particularly to a vacuum type dispensing head that is capable of delivering measured amounts of iodine to tubular quartz lamps.

Briefly, incandescent lamps having quantities of iodine in the envelope are known to the art. Such lamps operate yon a tungsten-iodine cycle which is a regenerative continuing process whereby tungsten iodide is produced when iodine combines chemically with particles of tungsten evaporating from an incandescing tungsten filament. Subsequent thermal decomposition of this compound replaces the tungsten particles on the filament. In conventional filament lamps not containing controlled quantities of iodine, these particles are deposited on the envelope thus gradually causing a loss of light output due to blackening Rupturing of the filament may occur when a sufiicient quantity of tungsten particles evaporate and the lamp must be replaced. However, the iodine-tungsten cycle eliminates lamp blackening and reduces outage by its getter action.

The iodine, together with the heat of the lamp, prevents the tungsten from .accumulating on the lamp envelope and darkening it. As the vaporized tungsten iodide circulates back into the area of the inc-andescent filament, th-e intense heat of the filament frees the tungsten iodide by thermal decomposition, and this tungsten is deposited back on the filament, leaving the iodine free to begin a new cycle. Theoretically, if the evaporating tungsten particles could be returned to the filament i-n a perfectly even coating, the lamp might burn indefinitely, But since there is no way to control exactly the return of the tungsten particles to the filament, one spot will eventually wear out, thus rendering the iodine-quartz lamp inoperative. This condition, however, occurs after operation in the order of hundreds of hours and possibly even thousands of hours before lamp failure. Furthermore, during the life of an iodine lamp, the maintenance of light output is substantially constant.

The iodine present in the lamp envelope must be in controlled quantities and in particular, must be in .an adequate quantity to effect a regenerative getter action, but inadequate to absorb appreciable quantities of light. Previous methods of adding the iodine to the lamp envelope to effect such regenerative getter action have been tedious and time consuming and, furthermore, have tended to introduce undesirable impurities into the lamp which shortens its life.

Such methods consisted of installing traps to hold the iodine crystals in the ex-haust tube, the traps being necessary to position the iodine securely during exhaust and fill steps. But this method sometimes caused impurities to enter the lamp envelope. One ofthe improvements over this process is described in U.S. Patent 3,063,778 to Emery Audesse, entitled Method of Introducing Iodine in a Lamp Envelope.

In the method described by Audesse, a quantity of iodine crystals are ground -to a desired diameter and inserted into the exhaust tube. The iodine crystals are then melted by warming the exhaust tube over a gas flame, causing the melted iodine to wet the inside wall of the glass. Upon cooling, the iodine solidies and adheres to the internal surface. The exhaust tube is then tipped, thus sealing the iodine from the atmosphere. The sealed lamp is then placed in a hot oil bath for an extended period of time for the purpose of vaporizing a needed amount of iodine into the glass envelope, Thereafter, the lamp envelope with its long appended exhaust tube is immersed in a cold water bath. This prevents residual and unvaporized iodine from falling from the exhaust tube into the lamp envelope. A chilling operation is the next step which consists of immersing the lamp assembly into a bath of liquid nitrogen. Chilling reduces the internal gas pressures of the lamp for the final tipping operation of the exhaust tube. The final tipping operation separates from the exhaust tube adjacent to the lamp envelope.

The method described above although quite accurate in dispensing quantities, tends to be rather time consuming and hence has a definite drawback as far as the present day high production methods 'are concerned.

The advantages of our invention are numerous in that we have a savings of material, such as iodine, gas lill and exhaust tube length. A savings in time is also -realized since our method takes only approximately 3 minutes to complete Whereas the old method took a matter of hours. Handling is also reduced which increases the final production of the lamps and attains high qualities.

Accordingly, an object of our invention is to prepare incandescent lamps having controlled quantities of radditive in the envelopes, entirely at one handling of the lamp.

Another object of our invention is to introduce iodine into lamp envelopes in a manner as to avoid contaminating and further, to produce lamps containing uniform quantities of iodine.

An advantage of our invention is that lamps containing uniform quantities of iodine may be produced without introduction of undesirable contaminating material.

Other objects, features and advantages will become apparent to those skilled in the art upon reading the following specication when taken in conjunction with the accompanying drawings in which:

FIGURE 1 is a partially-sectioned perspective view of the dispensing head showing in particular the fill and evacuating paths.

FIGURE 2 is an elevational cross-section of the dispensing head and lamp before the introduction of the iodine into the lamp.

FIGURE 3 is an elevational cross-sectional View of the dispensing head during the introduction of the iodine into the lamp envelope,

As mentioned above, our invention centers around a fully automated vacuum dispensing head, the unique concept of which not only improves the quality of the finished lamps, but increases the quantity of finished lamps. A number of these dispensing heads can be afiixed to a rotary indexing machine, and will increase the productivity of lamp manufacturing manyfold.

As seen in FIG. l, a dispensing head 10 of our invention is shown in perspective with a vertical segment cut away to show the internal structure of the head. This view in particular illustrates the main elements of the head and their working relationship to one another.

There are basically four main elements 4to the -dispensing head: a reservoir 12, a heater block 14, `a manifold block 16 and an adjustable clamping cap 18. Between these elements there are series =of hollow spacers that secure and space the elements from one another.

The manifold block 16 has a hollow cylindrical extension 48 directed from its bottom surface. This extension is provided with .a quick turn thread that allows maximum adjustment with the minimum of movement. A thread of the same description is also present on the interior of the adjustable cap 18. The cap 18 can be rotated to a position to receive an exhaust tube 22 of a quartz lamp 24 and thereafter the cap 118 can be rotated in the opposite direction to hold the lamp 24 in place during operation ofthe valve.

With the arrangement of the hollow spacers 20 located between the elements, a central vertical .passageway or bore 26 is defined, starting at the bottom in the adjustable cap 18 to the interior of the top reservoir 12. The diameter of the bore of the vertical passageway 26 varies in each element, depending on the function of the element.

A description of the individual elements will now be made to show their operancy and their relative location. The reservoir 12 positioned at the top of the dispensing head is cylindrical in shape and includes a body portion 28, having a counter bore that defines a well 30, the center portion of which is provided with a stand tube 32, extending part way to the top of the well. The top of the stand tube 32 is provided with a small orifice 33 which is the terminating extent of the passageway 26. In the operation of the dispensing head, the reservoir must be hermetically sealed during operation. This is accomplished by providing a suitable cover plate 34 with a series of screws 35 in cooperation with an O-ring gasket 36 that is positioned in the lower surface of the cover plate.

Spaced below the reservoir 12 and in cooperation relationship therewith is a U-shaped heater block 14, the main function of which is to heat a toggle valve 60 held within the confines of its U-shaped form. The toggle valve 68 is shown in phantom lines in FIG. l but can be viewed in FIGS. 2 and 3 in its open and closed positions. Located directly below and spaced from the heater block 14 is the manifold block 16 which has a slightly larger counterbore 40 than that of the heater block 14. From the interior of this counterbore 40 a pair of horizontal orifices 41 extend to adjacent rear corners of the manifold block. One of the orifices 41 can be clearly seen in FIGS. 2 and 3. The terminating ends of the orifices 41 are joined by formed metal tubes 44, 4S that are welded to the exit ports of the orifices. These tubes extending rearwardly and are provided at their distal ends with conventional supply hoses 46 and 47.

The lamp holding means located on the lower portion of the dispensing head includes a series of components fitted into the counterbore of the extension 48. They include a tube stop 50, a rubber bushing 52, a bearing disc 53, a washer 54 and a tube guide 56. These components are stacked in the counterbore and are held in place by the outer clamping cap 18. The fiared portion tube guide 56 extends through a suitable hole in the cap to provide guidance for the exhaust tube.

With the above described arrangement, the lamp 24 and the exhaust tube extension 22 can be inserted into the adjustable cap 18 until the end of the exhaust tube contacts the tube stop 50. Thereafter the adjustable cap 18 is turned to compress the rubber bushing 52 against the wall of the exhaust tube 22. The lamp 24 is securely held in this position during the entire operation.

A series of conventional electrical cartridge heaters 58 are installed in spaced apart bores positioned in each of the main elements such as the reservoir 12, the heater block 14 and the manifold block 16. These cartridges heat the particular element to a desired temperature for the proper operational environment. A more detailed description will be given hereinafter.

As mentioned above, the heater block 14 is U-shaped and such that a conventional toggle valve 60 is held within the confines thereof. The valve 60 includes a cylindrical plunger 61 that fits snugly into a horizontal mating bore 62. The length of bore 62 is such that it bisects the vertical passageway 26 and thus when the plunger 61 is fully seated in the bore 62 it completely blocks a restricted opening 63 located in the valve body 64. With the above described arrangement the valve 60 controls the amount of materials, in this case iodine vapor, that can pass through the passageway 26.

As viewed in FIGS. 2 and 3, the valve 60 is pivotally fixed to an angle bracket 65 which in turn is securely attached to the manifold block 16. FIG. 3 shows a view of the valve 60 in its operational phase that is, when it is actuated, by a pneumatic plunger 68. It can be seen in this view that when a lamp 24 is in place and is in register with the passageway 26, a clear path is defined from the reservoir to the lamp.

To illustrate the process, reservoir 12 is loaded with a quantity of iodine crystals 69, in this case about l2 grams in weight. This is accomplished by removing the cover 34 and placing the iodine crystals 69 in the reservoir cavity 30. The cover 34 including the O-ring gasket 36 is fitted back on the reservoir and tightly secured in place by the screws 35, making a vacuum tight cavity within the reservoir 12.

A lamp envelope 24, made from fused crystalline quartz or similar material having an appended exhaust tube 22 depending therefrom is then inserted into the adjustable screw cap 18. The depth of insertion of the exhaust tube is limited by a tube stop 50 located at the top of the adjustable cap 18. This tube stop 50 will also align the exhaust tube 22 with the vertical passageway 26 of the dispensing head.

FIG. 2 exhibits the condition of the dispensing head 10 at the above described phase of operation, where a lamp envelope 24 is in position to receive a quantity of iodine vapor from the reservoir 12. Before the iodine delivery sequence, a number of functions will have to be performed, mainly the glass lamp envelope 24 must be pumped and iiushed in the usual manner prescribed in lamp manufacturing. The pumping and flushing supply lines are located at the rear corners of the manifold block, both of which are connected to the horizontal orifices terminating in the bore of the manifold. The flushing generates from a tank through supply line 46 to the tube 44 to the manifold block 16 and thence to the lamp envelope 24 thereby ushing the envelope. In return the gasses pass over a path through the tube 45 and supply line 47. The drawing of vacuum occurs directly over the supply line 47 and the tube 45 to evacuate the lamp envelope to a pressure of between 20-25 microns. At this time another important condition must be met, that is the vertical passageway 26, including the exhaust tube 22 of the lamp 24 must be heated to a dispensing temperature. The iodine vapor must be heated to a temperature which will allow it to travel from the reservoir 12 along the length of the passageway 26 to the lamp envelope 24 before it condenses. The heating of the passageway 26 including the reservoir 12, heater block 14 and the manifold 16 is accomplished by the use of suitable cartridge heaters 58 located in each component. To completeV the heating of the dispensing passageway 26, the appended exhaust tube 22 is also heated by adjacent hot air heaters 72.

Simultaneously with heating of the exhaust tube, a cold spot 74 is generated on the lower part ofthe glass envelope 24 which is in line with the appended exhaust tube 22.

All of the conditions are now met for dispensing a quantity of iodine vapor to the lamp envelope. As viewed in FIG. 3, a remotely operated plunger 68 is initiated to pivot the toggle valve arm 66 which will retract its plunger 61 in the bore 62. This action clears the passageway 26, thereby defining a clear path from the reservoir 12 to the lamp envelope 24 where a predetermined amount of iodine vapor will travel from the reservoir 12 over the heated passageway to the lamp envelope 24 where it will adhere and condense on the generated cold spot 74.

We prefer to hold the valve open approximately 11/2 seconds to dispense iodine quantities of at least 0.1 micromole to 1.0 micromole per cubic centimeter of bulb volume.

The amount of iodine vapor dispensed to a lamp envelope can be controlled by the time the valve 60 is held open or by varying the temperature of the reservoir 12.

After completion of the iodine dispensing cycle, a series of fill gases are placed in the lamp through supply line 46, tube 44, orifice 41 by way of the manifold block 16 to the lamp envelope 24. We use for example a fill `gas or argon or nitrogen or a proportion of both a pressure of 700 mm. to 2%. atmospheres depending on the type of lamp being fabricated.

The lamp is now ready for cooling or chilling prior to the final tipping to remove the appended exhaust tube 22. The chilling operation is necessary to reduce the internal gas pressures so that the removal and sealing of the exhaust tube port can be facilitated. The separation of the lamp envelope 24 from its exhaust tube 22 completes the fabrication of a lamp. The removal of the exhaust tube from the adjustable cap 18 and flushing of the passageway 26 of the dispensing head is then performed. This places the dispensing head in a condition to receive a new exhaust tube and lamp for fabrication. From the above description it can be seen that our dispensing head has many advantages. For example a iill of about 12 grams of iodine in the reservoir is enough to process up to 3,500 lamps, and with a plurality of such heads as in an indexing machine, a very high lamp production of uniform quality can be attained. Also the diversification of the head is such that an unlimited number of lamps can be processed with a few more adjustments to the head.

It is apparent that changes and modifications may be made within the spirit and scope of the instant invention. It is our intent, however, to be limited only by the scope of the appended claims.

What we claim is:

1. An iodine `dispenser comprising: a dispensing head containing a vacuum tight iodine reservoir; a heated vertical bore extending downwardly from said reservoir; a valve disposed beneath said reservoir and in communication with said vertical bore; a heater operatively associ-ated with said valve; a manifold disposed beneath said valve; an exhaust tu-be holder disposed beneath said manifold; whereby the exhaust tube of a lamp to be lled is received and held in said holder and a quantity of iodine vapor can be dispensed from said reservoir by initiating said dispensing valve.

2. The combination of claim 1 in which said vertical bore extends into said reservoir short of the height of said interior cavity.

3. The combination of claim 1 further including a restricted orifice disposed within said Vertical bore and operatively associated with said Valve means; said valve means including a reciprocating plunger disposed within said vertic-al bore.

4. The device according to claim 3 including means to heat the exhaust tube.

5. An iodine dispenser comprising: a vacuum tight reservoir means for retaining iodine; a heated vertical bore extending downwardly from the interior of said reservoir means; heater means disposed about said vertical bore; valve means extending into said vertical bore to stop the flow of gases from passing therethrough; a heated manifold disposed beneath said valve means and in gas flow relation therewith; retaining means for holding an exhaust tube of a lamp disposed beneath said manifold, the interior of said exhaust tube being in communication with said manifold, whereby iodine vapor can be `dispensed from said reservoir through said vertical bore; over said valve means, though said manifold and into said exhaust tube of said lamp.

6. The combination of claim 5 including means to heat said reservoir at a temperature to induce vaporization of said iodine.

7. The combination of claim 5 including means to admit and remove gases to said lamp through said manifold.

No references cited.

RICHARD H. EANES, I R., Primary Examiner. 

1. AN IODINE DISPENSER COMPRISING: A DISPENSING HEAD CONTAINING A VACUUM TIGHT IODINE RESERVOIR; A HEATED VERTICAL BORE EXTENDING DOWNWARDLY FROM SAID RESERVOIR; A VALVE DISPOSED BENEATH SAID RESERVOIR AND IN COMMUNICATION WITH SAID VERTICAL BOREF A HEATER OPERATIVELY ASSOCIATED WITH SAID VALVE; A MANIFOLD DISPOSED BENEATH SAID VALVE; AN EXHAUST TUBE HOLDER DISPOSED BENEATH SAID MANIFOLD; WHEREBY THE EXHAUST TUBE OF A LAMP TO BE FILLED IS RECEIVED AND HELD IN SAID HOLDER AND A QUANTITY OF IODINE 